Cause of the Minneapolis 35-W Bridge Collapse Revealed

With little fan fair and not much publicity from major media outlets, the National Safety Transportation Board (NTSB) released their findings of the cause of the horrific 35-W bridge collapse that occurred back on August 1st, 2007 in Minneapolis. According to the NTSB, a design error led to undersized gusset plates being used for the construction of the steel-deck truss bridge that opened for public use back in 1967. According to their findings, the gusset plates, which connect steel beams, were only half as thick as required for the bridge to meet federal guidelines. Thirteen (13) people were killed and more than 100 were injured when the bridge fell without warning into the mighty Mississippi River.

As I discussed in my previous article on this topic titled "The State of US Infrastructure," it was noted that the 35-W bridge was deemed "structurally deficient" by the Federal Government as far back as the year 1990. With the latest NTSB findings, the question of why the undersized gusset plates used for the construction of the bridge were not discovered during the multitude of additional bridge inspections that occurred over its 40 year lifetime.

Although the families of the bridge collapse victims may find some peace and gain some closure with the NTSB's findings, I still personally feel that the tragic accident was preventable and more should be being done now to ensure another horrific disaster like the 35-W bridge collapse doesn't occur again in the future.

Sources used for this article:

1.) http://kstp.com/article/stories/S313639.shtml?cat=118
2.) http://www.ntsb.gov/

The State of Pennsylvania Bridges

Since the deadly Minnesota bridge collapse of I-35W back on August 1, 2007, which I wrote about here on my blog, I have been on a mission to find more information on the condition of the 25,000 state-owned bridges in Pennsylvania. What I have found out is disturbing and scary to say the least.

According to a Pennsylvania Department of Transportation (PennDOT) report on PA Bridges, Pennsylvania has the largest number of structurally deficient bridges in the nation – nearly 6,000 statewide. A structurally deficient bridge is defined as being safe, but in need of costly repairs or replacement to bring it up to current standards.

PennDOT does have in place what is calls an “aggressive” bridge inspection program that calls for regular inspections of all Pennsylvania bridges at least once every two years, with structurally deficient bridges being inspected more frequently if their condition warrants.

Does this inspection program make you feel safe while driving over a local bridge? I know that I personally say a prayer every time I cross a bridge in Pennsylvania now. Maybe it is because of the horrifying images I saw from the Minnesota bridge collapse that is causing my fear. However, when you look at the numbers, my fear may be justified.

According to the Philadelphia Inquirer, Bridge inspectors give each bridge a “sufficiency rating” rating on a 0-to-100 scale, using a formula that evaluates safety, serviceability, and how essential the bridge is. And they assign a condition rating for each of its three primary components (deck, superstructure and substructure) on a 0-to-9 scale (0 = failed [out of service and beyond corrective action], 1 = closed, 2 = critical, 3 = serious, 4 = poor, 5 = fair, 6 = satisfactory, and 7, 8, or 9 = good). A structurally deficient bridge is one for which the deck, superstructure or the substructures are rated in condition of 4 or less.

Minnesota’s I-35W bridge had a sufficiency rating of 50, a deck score of 5 (‘fair”), a superstructure score of 4 (“poor”), and a substructure score of 6 (“satisfactory”), as of the last Minnesota Department of Transportation (Mn/DOT) Bridge Inspection Report dated 06-15-2006. To date, the cause of this bridge collapse is still unknown.

According to the research conducted by Paul Nussbaum, Transportation Reporter for the Philadelphia Inquirer, the eight-county Philadelphia region has 57 bridges that carry at least 25,000 vehicles daily and have ratings at least as low as the Minnesota I-35W bridge. Additional disturbing, yet eye-opening findings from Paul’s research include:

• The worst local bridge, according to sufficiency and condition ratings, is the DeKalb Pike Bridge located in Bridgeport, PA. This bridge scores a sufficiency rating of 3 out of 100, a substructure rating of 2 (critical), and a superstructure and deck rating of 4 (poor) respectively. This bridge carries U.S. 202 over the Norfolk Southern railroad tracks and remains open without weight limitations.



• I-95 has more deficient bridges than any other highway in the region at 15. The Pennsylvania Turnpike has 7 bridges rated deficient and the Schuylkill Expressway has one bridge rated deficient.



• Of the major Delaware River bridges in the region, only the Burlington-Bristol Bridge is rated structurally deficient.

For an interactive map of the bridges in the worst condition in the Philadelphia region, check out this tool provided by The Philadelphia Inquirer.

Despite the engineering reports and the independent research that highlights the dire condition of Pennsylvania bridges, state officials continue to assert that the bridges remain safe. But Minnesota officials thought the same thing about the I-35W Bridge before it collapsed into the murky Mississippi River. And that bridge was rated significantly higher across the board that most of Pennsylvania’s bridges.

Pennsylvania has at least acknowledged the troubled state of its transportation infrastructure. According to PennDOT, Pennsylvania has made significant investments to improve bridge and highway infrastructure in the state. Last year alone, PennDOT invested $558 million in 894 bridge projects statewide, with $425 million of this budget being devoted to the rehabilitation and replacement of structurally deficient bridges.

Clearly, Pennsylvania has taken a step in the right direction, to ensure the safety of our bridges. But because the state currently has such a large amount of structurally deficient bridges, it will take decades to complete them all. This means that, in the interim, we must take our chances driving over the nation’s worst bridges daily. Comforting isn’t it?

Let me know what you think of the state of Pennsylvania’s bridges by leaving me a comment.

The State of US Infrastructure

The horrific bridge collapse that occurred in Minnesota this week is one of those unexplainable events that will change so many lives forever. My hopes and prayers go out to everyone affected by this accident, especially the friends and family of those killed. Words cannot describe the pain being felt today - Pain that will take a very long time to fade away.

The important question now being asked across America is “Are our nation’s bridges safe?” And the answer to that question is unsettling and down right scary. According to the most recent Infrastructure Report Card issued by the American Society of Civil Engineers (ASCE), our nation’s public infrastructure is in a crisis situation. For example, as of 2003, 27.1% of our nation’s bridges (160,570 in total) were classified as structurally deficient or functionally obsolete (ASCE, 2005).

A structurally deficient bridge is defined as a bridge that is closed or restricted to light vehicles because of its deteriorated structural components. While not necessarily unsafe, these bridges must have limits for both speed and weight (ASCE, 2005). A functionally obsolete bridge is defined as a bridge that has older design features and, while it is not unsafe for all vehicles, it cannot safely accommodate current traffic volumes, and vehicle sizes and weights (ASCE, 2005).

Bridges in our country are critical elements of our highway transportation system. Everyday, our nation’s vehicles cross bridges close to 4 billion times (Purdy, 2005). But it is now unfortunately clear that the infrastructure of our country is deteriorating – and at an alarming rate.

Up until the bridge collapse in Minnesota, most Americans were unaware of the extent of the problem. Even worse, it is currently impossible to get information about the structural rating of a specific bridge. In Pennsylvania, The Beaver County Times & Allegheny Times newspaper formally requested specific rankings of structurally deficient bridges on the area under the State’s Right to Know Law. However, this request was formally denied by the PA State Department of Transportation (PennDOT), saying the information requested was not a public record as defined by law.

I find it extremely unsettling that our government knows this information and yet still refuses to make it public. How many of the victims from Thursday’s horrific accident in Minnesota would have chosen a different route across the mighty Mississippi River had they know the 35W bridge was deemed structurally deficient? I find it almost criminal to not disclose this information.

Clearly, the way our government is running our great country (literally into the ground) needs to change. Increased funding is now an absolute necessity to improve our nation’s infrastructure. However, these improvements will not be cheap. According to the National Bridge Investment Analysis System (NBIAS), an investment of $54.7 billion will be needed to improve just the bridge deficiencies based on the year 2000 data. The annual cost to eliminate deficiencies is estimated to be $9.4 billion per year over the next 20 years. And this amount would only address current bridge deficiencies.

Now is the time for our country to band together and demand that our government stop wasting tax payer money on pork barrel items (like the bridge to know where in Alaska) and start truly focusing on our nation’s critical problems. American’s should not be subject to fear and anxiety when they have to cross a bridge in their own country. But unfortunately, the tragic events of August 2, 2007 have changed that state of mind forever. The time is now to make things right, so future generations of hard working Americans will not have to experience the paid of another infrastructure tragedy that could have been avoided.

Sources:

The ASCE Infrastructure Report Card 2005. http://www.asce.org/reportcard/2005.

Purdy, Diane, 2005. The Pennsylvania Local Roads Program: Condition of Bridges. Technical Information Sheet #119. University Park, PA.